Author Topic: CB500 - Will only start with starter motor  (Read 1533 times)

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Offline haydo147

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CB500 - Will only start with starter motor
« on: August 24, 2022, 07:11:42 PM »
Hi all,

My CB500 has been running well the last few months, however I haven't been able to kick start it at all.

With the starter, I can get it running when cold after a few seconds of starting. However, no matter how cold or warmed up it is, I cannot get it to start by kicking. It doesn't even sound like its close to starting when I kick it.

I'm currently running the following setup:
Carburetor model: 069A
Exhaust: 4 into 1 exhaust with a muffler
Pilot Jet: 38
Main Jet: 105
Needle clip position: Second from top
Intake: UNI pod filters
Ignition: 4into1 ignition coils with kokusan electronic ignition
Battery: Anti-gravity 8-cell battery

I have given it a valve adjustment and also checked dynamic timing.

My concern is maybe that compression is a bit low, which might be causing this issue. But it also feels quick enough so I'm not sure. I got the following compression numbers when I tested it. I also provide my compression test for my 2008 Suzuki GS500 below (which runs perfectly fine) for reference, as I think my compression tester isn't the greatest.
Compression:
Without oil:
Cylinder 1: 66psi
Cylinder 2: 55psi
Cylinder 3: 63psi
Cylinder 4: 65psi

With oil:
Cylinder 1: 76psi
Cylinder 2: 60psi
Cylinder 3: 65psi
Cylinder 4: 76psi

GS500:
Without oil:
Cylinder 1: 87psi
Cylinder 2: 92psi


Does anyone have any guidance on whats going on here?

Offline grcamna2

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Re: CB500 - Will only start with starter motor
« Reply #1 on: August 24, 2022, 07:15:26 PM »
What type of compression tester gauge and connector hose are you using to measure with ? and are the engines cold or hot when taking the readings ?
A hot/warm engine will give more accurate readings.

Those numbers seem way too low  :o
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Re: CB500 - Will only start with starter motor
« Reply #2 on: August 24, 2022, 07:25:51 PM »
^ I agree, those compression readings are bogus for both bikes. ;)
Check your ignition timing: retarded timing makes an engine need to spin faster to start, and sounds/feels like it has low compression, while advanced timing will make the engine act like it has more compression and can make the starter struggle.   
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Offline haydo147

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Re: CB500 - Will only start with starter motor
« Reply #3 on: August 24, 2022, 08:02:04 PM »
Haha yeah I agree with you both! It's the second compressor tester I've bought and it's still having issues. I make sure to have it WOT and warm as well. The hose is around 30cm long. It was just one of those standard ones I bought from my local automotive shop.

I'll double check the ignition timing and see how I go.

Could the carbs be causing this kind of issue?

Online bryanj

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Re: CB500 - Will only start with starter motor
« Reply #4 on: August 24, 2022, 08:03:35 PM »
That gauge is junk
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Offline haydo147

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Re: CB500 - Will only start with starter motor
« Reply #5 on: August 25, 2022, 06:00:38 AM »
Yeah I figured it was pretty average.

I don’t think compression is the issue though, especially given I can’t hear it firing at all with a kick start. I confirmed the timing today with a strobe light and it was right on the firing line.

What I did find today was that there isn’t any spark when I try to kick start it. I removed the spark plug and looked for a spark with the light off, and couldn’t see anything. So l thinking maybe now it’s a spark related issue. I forgot to mention earlier that I use a moto gadget m unit, so I’m thinking maybe the issue lies there.

Offline Scootch

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Re: CB500 - Will only start with starter motor
« Reply #6 on: August 25, 2022, 08:13:15 AM »
I think you are on the right track in realizing that you don't have spark unless using the electric start. Perhaps a power or ground or wiring problem?? Loose or intermittent connection??

Offline calj737

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Re: CB500 - Will only start with starter motor
« Reply #7 on: August 25, 2022, 06:59:28 PM »
What I did find today was that there isn’t any spark when I try to kick start it. I removed the spark plug and looked for a spark with the light off, and couldn’t see anything. So l thinking maybe now it’s a spark related issue. I forgot to mention earlier that I use a moto gadget m unit, so I’m thinking maybe the issue lies there.
The mUnit should be activated either by your key, Bluetooth, or the mKey. Which method do you use? Once active, the IGN out should be providing power to the coils (12v) if you Kill/Run switch on the handlebars is in correct position. The other thing to consider is a clutch safety switch. Did you wire one in? Are you in NEU while trying to kick the bike? Are you holding the clutch while kicking or using electric start?

Let’s get some answers to these questions and the remedy will be quick.
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Offline haydo147

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Re: CB500 - Will only start with starter motor
« Reply #8 on: August 26, 2022, 07:51:19 AM »
I activate it either by key or Bluetooth. I have tried using both and still have the same issue.

I confirmed 12V to coils (through the black and white wire) when the kill switch (push button in my case) is pushed on.

No clutch safety switch in mine.

Yep I’m in neutral when kicking. I also tried kicking it over in first gear with the centre stand down.

Not holding the clutch in when starting either by electric start or kick-start.

Offline TwoTired

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Re: CB500 - Will only start with starter motor
« Reply #9 on: August 26, 2022, 10:47:06 AM »
Compression is a function of piston swept displacement and cylinder head volume. Well, valve timing too.  But let’s not go into that right now.  If you add or increase cylinder head volume, the compression ratio goes down and you make less compression.  So, to get accurate pressure numbers the apparatus you use for the test must either add minimal volume to the chamber or have the release valve physically very lose to the spark plug hole, or you can expect lower than book values for your test, as they used an apparatus intended for small engine displacements.

069 a carbs came stock with solid tipped pilot screws and have a different taper angle than the hollow cross drilled screws used on other models. These are either set to factory numbers along with all the other stock components attached to the engine.  Or, they are adjusted for correct response from throttle twist under engine load to achieve reliable, if sluggish, pick up in any gear with up to one half throttle twist.  These screws adjust idle mixture over-rich just enough so that when the slides are lifted and vacuum is lost, causing less fuel drawn from all carb jets, the motor has enough residual fuel to increase rpm and restore vacuum draw from the jets.  The cross drilled pilot screws are a limiter on just how rich you can make the idle mixture.  As Honda knew that if you make the mixture too rich, the spark plugs will carbon foul from long idling periods.   The 069a solid tipped screws were an attempt by Honda to allow fine tuning of the idle mix to allow passing the EPA demand for low idle emissions required in 1978.  This failed, because there is no provision for an accelerator pump to squirt gas into the carb throat to over come the unavoidable leaning caused by raising the mechanical slides.  It is also one reason why there are no 1978 F model 550s, as they could not meet 1978 EPA requirements without replacing the carbs.  069a carbs were only used on F model bikes from Honda.
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Offline calj737

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Re: CB500 - Will only start with starter motor
« Reply #10 on: August 26, 2022, 11:23:06 AM »
I confirmed 12V to coils (through the black and white wire) when the kill switch (push button in my case) is pushed on.
You have to hold the Kill switch to get 12v to the coils? That’s not right. Pushing that button should only trip the starter solenoid.
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Offline haydo147

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Re: CB500 - Will only start with starter motor
« Reply #11 on: August 28, 2022, 06:14:31 AM »
As in, when I push it in momentarily, it goes to ignition on (this is when my phone is in range of the motogadget m unit, as it unlocks the bike).

Compression is a function of piston swept displacement and cylinder head volume. Well, valve timing too.  But let’s not go into that right now.  If you add or increase cylinder head volume, the compression ratio goes down and you make less compression.  So, to get accurate pressure numbers the apparatus you use for the test must either add minimal volume to the chamber or have the release valve physically very lose to the spark plug hole, or you can expect lower than book values for your test, as they used an apparatus intended for small engine displacements.

069 a carbs came stock with solid tipped pilot screws and have a different taper angle than the hollow cross drilled screws used on other models. These are either set to factory numbers along with all the other stock components attached to the engine.  Or, they are adjusted for correct response from throttle twist under engine load to achieve reliable, if sluggish, pick up in any gear with up to one half throttle twist.  These screws adjust idle mixture over-rich just enough so that when the slides are lifted and vacuum is lost, causing less fuel drawn from all carb jets, the motor has enough residual fuel to increase rpm and restore vacuum draw from the jets.  The cross drilled pilot screws are a limiter on just how rich you can make the idle mixture.  As Honda knew that if you make the mixture too rich, the spark plugs will carbon foul from long idling periods.   The 069a solid tipped screws were an attempt by Honda to allow fine tuning of the idle mix to allow passing the EPA demand for low idle emissions required in 1978.  This failed, because there is no provision for an accelerator pump to squirt gas into the carb throat to over come the unavoidable leaning caused by raising the mechanical slides.  It is also one reason why there are no 1978 F model 550s, as they could not meet 1978 EPA requirements without replacing the carbs.  069a carbs were only used on F model bikes from Honda.

That makes sense from the compression testing side, I might just take it to a shop to get it compression tested with their equipment. Or potentially a leakdown test. I also took a different approach today and put new spark plugs in and tested kick starting from aerostart. Doing this allowed me to get it to start on first kick. So it sounds like the spark is fine after all, it's just the carb that seems to be the issue.

So you think it would be worth getting CB500 cross-drilled pilot screws? I might look into replacing the needles with CB500 needles as well. The only kit I've seen is from 4into1.com. Not sure where I would be able to get OEM needs and pilot screws without spending a heap of money on ebay.


Offline calj737

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Re: CB500 - Will only start with starter motor
« Reply #12 on: August 28, 2022, 10:50:07 AM »
Well if IGN output is not active without phone and button depressed, then kicking it will become tricky. You should be able to excite the IGN by activating the mUnit with your phone so 12v is at coils without a button being depressed. Pressing the button moves the 12v to the solenoid for the START circuit.
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Offline haydo147

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Re: CB500 - Will only start with starter motor
« Reply #13 on: August 28, 2022, 08:34:42 PM »
The IGN output is active, it's just that the phone unlocks the bike, and then you double tap the button to go to ignition on. I checked the voltage at the coils and I'm getting 12V.

I also used aerostart on the engine after running the carb empty on fuel, and I could get the motor kick started once or twice using this method. As such,  I would assume I'm not having an ignition issue.

Also after doing a bit of research, some people have mentioned fuel may have an impact on these engines. I've been using 98 RON since I've had the bike. Could this impact kick starting?

Online scottly

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Re: CB500 - Will only start with starter motor
« Reply #14 on: August 28, 2022, 08:41:09 PM »
I also took a different approach today and put new spark plugs in and tested kick starting from aerostart. Doing this allowed me to get it to start on first kick. So it sounds like the spark is fine after all, it's just the carb that seems to be the issue.

What is "aerostart"? Is it ether starting fluid? Were the old spark plugs fouled?
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Offline haydo147

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Re: CB500 - Will only start with starter motor
« Reply #15 on: August 28, 2022, 09:09:31 PM »
Sorry, it's starting fluid.

And the spark plugs were fouled y eah. Which I thought was strange given that my jets weren't too large and my needle is in the second groove from the top.

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Re: CB500 - Will only start with starter motor
« Reply #16 on: August 28, 2022, 09:24:48 PM »
With clean plugs will it kick-start without starting fluid?
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Offline haydo147

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Re: CB500 - Will only start with starter motor
« Reply #17 on: August 29, 2022, 07:56:58 PM »
With starting fluid, it kick started a bit easier.

But it still doesn't kick-start with clean plugs without starting fluid.

Offline Quattrocilindri

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Re: CB500 - Will only start with starter motor
« Reply #18 on: August 31, 2022, 12:06:43 PM »
Hi all,

My CB500 has been running well the last few months, however I haven't been able to kick start it at all.

With the starter, I can get it running when cold after a few seconds of starting. However, no matter how cold or warmed up it is, I cannot get it to start by kicking. It doesn't even sound like its close to starting when I kick it.

I'm currently running the following setup:
Carburetor model: 069A
Exhaust: 4 into 1 exhaust with a muffler
Pilot Jet: 38
Main Jet: 105
Needle clip position: Second from top
Intake: UNI pod filters
Ignition: 4into1 ignition coils with kokusan electronic ignition
Battery: Anti-gravity 8-cell battery

I have given it a valve adjustment and also checked dynamic timing.

My concern is maybe that compression is a bit low, which might be causing this issue. But it also feels quick enough so I'm not sure. I got the following compression numbers when I tested it. I also provide my compression test for my 2008 Suzuki GS500 below (which runs perfectly fine) for reference, as I think my compression tester isn't the greatest.
Compression:
Without oil:
Cylinder 1: 66psi
Cylinder 2: 55psi
Cylinder 3: 63psi
Cylinder 4: 65psi

With oil:
Cylinder 1: 76psi
Cylinder 2: 60psi
Cylinder 3: 65psi
Cylinder 4: 76psi

GS500:
Without oil:
Cylinder 1: 87psi
Cylinder 2: 92psi


Does anyone have any guidance on whats going on here?

I feel stupid asking you this but:

When you do your compression test, do you have the throttle fully open? If not, the cylinders cannot bring in enough air to get a more normal reading of 120-160 PSI.

Also, since you have the pod filters, your idle jets # 38 might be too lean for the reduced intake air vs. standard air box.

Offline grcamna2

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Re: CB500 - Will only start with starter motor
« Reply #19 on: August 31, 2022, 12:11:59 PM »
Try closing the throttle while cranking it to start:keep it closed,this will allow more fuel to be drawn up through the carbs by vacuum.
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Offline haydo147

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Re: CB500 - Will only start with starter motor
« Reply #20 on: June 20, 2023, 07:18:42 PM »
Okay so after a few months of frustration and tinkering with other issues, I'm back to fixing this (sigh)....

Since my last post, I've reverted back to an airbox setup with a 3d printed intake pipe so I can fit a 2.5" air filter.

My current carburetor setup is as follows:
Pilot Jet: 40
Main jet: 105
Needle clip: 3rd position


I also did another compression test, this time using the push in type rubber attachment. This seems to have given me some more accurate readings:

Dry test:
Cylinder 1: 147psi
Cylinder 2: 115psi
Cylinder 3: 139psi
Cylinder 4: 147 psi

Wet test:
Cylinder 1: 185psi
Cylinder 2: 147psi
Cylinder 3: 162psi
Cylinder 4: 173psi

Would anyone know if this readings are something to be concerned about? And if this could be the cause for my bike not starting from the kick start?

Offline ekpent

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Re: CB500 - Will only start with starter motor
« Reply #21 on: June 20, 2023, 08:00:30 PM »
Are you still using that high octane premium gas ? Probably will run better on the cheap low octane stuff and be better for the plugs.

Offline haydo147

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Re: CB500 - Will only start with starter motor
« Reply #22 on: June 20, 2023, 09:28:23 PM »
Not anymore, I've just been running regular 91  (Australian 91 fuel) for the last few months

Offline CycleRanger

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Re: CB500 - Will only start with starter motor
« Reply #23 on: June 20, 2023, 11:12:48 PM »
How is your clutch? If your clutch plates are worn and slipping a bit that can make it harder to kick over whereas the starter motor can spin it fast enough to overcome the slippage and start the engine.
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Offline haydo147

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Re: CB500 - Will only start with starter motor
« Reply #24 on: July 05, 2023, 04:30:10 AM »
I didn't consider the clutch, that's definitely something I haven't checked yet! Though I haven't noticed any issues with my clutch really, can't say I've felt it slipping (unless I just haven't been noticing it). I might buy some heavy duty springs to increase the clamping force, and see if that makes any difference to kick-starting.

Otherwise, I've got a leak-down test booked in with my local motorcycle mechanic in a few weeks, so that may give a more accurate insight into my compression.

Offline haydo147

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Re: CB500 - Will only start with starter motor
« Reply #25 on: July 11, 2023, 03:13:22 AM »
Alright so I bought some heavy duty clutch springs and put them in today to see if there was any difference....sadly still doesn't kick start at all.

Any other ideas for what the issue could be? I've run out of any potential ideas to try >:(